The three stars all left before the end of the relatively brief run. The final performance for both Pearl Bailey and Georges Guetary was May 13, 1950 (although it seems possible that Bailey had not performed in the show for at least a few days before that). Nanette Fabray seems to have played her final performance on May 15, although she remained listed in ads for the production through May 20. But according to an item in a New York Times theatre column on Friday, May 19, 1950, Fabray had been missing from the musical since Tuesday of that week. It was reported that she had left on the advice of her physician, and her condition was descibed (in quotation marks) as "run-down." Fabray's understudy, Mary O'Fallon, closed the run.
It had been announced in early May that John Tyers would replace Guetary on June 1. When Guetary left two weeks before that, Larry Douglas took over on what was supposed to be a temporary basis. Douglas was supposed to join Where's Charley? on Friday, May 26, replacing Byron Palmer as Jack Chesney. Tyers was then supposed to take over from Douglas in Arms and the Girl on that date. When Fabray also left and ti became clear that the show would close, it seems that Douglas played out the end of the week rather than having Tyers come in for the last two days, although it does seem that playbills with Tyers listed had already been printed and were handed out.
We think that Douglas must have been the understudy for the role, although we have no playbills listing him as understudy. When the production opened, Stephen Douglass was the understudy, but he would open in Carousel in London on June 7 so he must have left by early May (if not earlier).